No, there is no minimum count for the topologies. Even single triangles can be turned into topologies, so there must be something particular about the low-poly geometry you're using. If you have used the subdivide tool, chances are it fixed whatever was the problem. Look out for lamina faces (faces with zero area), unconnected vertices, unconnected edges, zero-length edges...that kind of stuff. Maya's "cleanup" should take care of most of that, though. Also make sure your normals point in consistent directions, as that can sometimes affect triangle winding. cheers!